Polymeric wood preservative compositions

ABSTRACT

The present invention relates to a method and a wood preserving composition which is free of poly-aspartic acid and its derivatives and comprises mixtures of a metal compound, complexing agents selected from ethanolamines, polyethylenimine, ammonia or a mixture of these compounds, and a vinyl based polymer selected from poly(vinyl alcohol) (PVA), poly(acrylamide) (PA), poly(N-vinyl pyrrolidone) (PVP) and poly(N-isopropyl acrylamide) (PNIPAM). The resulting metal amine solution can then be used to formulate a variety of metal-based cellulosic material preserving products.

RELATED APPLICATION MATERIAL

This application is a continuation-in-part of application Ser. No.10/627,885, filed Jul. 25, 2003, which claims priority to provisionalapplication Ser. No. 60/399,071, filed Jul. 26, 2002, the disclosures ofwhich are incorporated by reference herein.

BACKGROUND

Wood preserving compositions are well known for preserving wood andother cellulose-based materials, such as paper, particleboard, textiles,rope, etc., against organisms responsible for the destruction of wood,namely fungus and insects. Many conventional wood preservingcompositions comprise copper amine complexes. Copper amine complexeshave been used in the past because the copper in such complexes issoluble in aqueous solutions. The copper in the copper amine complexesis typically obtained from a variety of copper bearing materials, suchas copper scrap, cuprous oxide, copper carbonate, copper hydroxide, avariety of cuprous and cupric salts, and copper bearing ores. The aminein such copper amine complexes is normally obtained from an aqueoussolution of ammonia and ammonium salts such as ammonium carbonate andammonium sulfate.

A conventional method to prepare such copper amine complexes isdisclosed in U.S. Pat. No. 6,340,384. In that patent, the inventorwrote, “The copper amine complex may be prepared by methods known in theart. For example, U.S. Pat. No. 4,622,248 describes forming copper aminecomplexes by dissolving copper oxide in ammonia in the presence ofammonium bicarbonate.” Another method to form cupric oxide and cupricoxide amine complexes is disclosed in U.S. Pat. No. 5,492,681 to Paseket al. Pasek et al. describe a process to produce cupric oxide fromcopper bearing materials with aqueous ammonia and an ammonium salt inthe presence of oxygen to form a cupric amine compound which, uponheating, decomposes to cupric oxide, ammonia and water.

The disadvantage of using aqueous ammonia as copper solubilizing agentlies in the strong odor of ammonia. Additionally, copper ammoniapreservatives can affect the appearance of the treated wood givingsurface residues and undesirable color. In recent years, manyamine-containing compounds, such as ethanolamines and aliphaticpolyamines, have been used to replace ammonia to formulate water-solublecopper solutions. These compounds were chosen because of their strongcomplexing ability with copper and the absence of undesirable odor. U.S.Pat. No. 4,622,248 discloses a method of preparing copper aminecomplexes by dissolving a mixture of copper carbonate [CuCO₃] and copperhydroxide [Cu(OH)₂] in ethanolamine and water. The complexing amine andcopper combine stoichiometrically in a 4 to 1 (molar ratio) and thus theweight ratio of reagents will be different for each complexing amine.However, copper amine based preservatives, such as coppermonoethanolamine (Cu-MEA), have higher copper loss due to leaching ascompared to a traditional copper based preservative chromated copperarsenic (CCA). The high copper leaching in Cu-MEA is believed to be dueto the strong complex which forms between the cupric ion andmonoethanolamine (MEA). For example, more than 25% of copper present inthe treated wood can be leached out when wood is treated with a Cu-MEAsolution containing 0.5% copper. Although not desiring to be bound byany particular theory, the inventors believe that as the amine compound,such as MEA, is leached from the treated material, the strong complexbetween Cu-MEA results in the leaching of copper along with the leachedMEA.

In an attempt to remedy the leaching of copper alkanolamine complexesfrom treated wood, U.S. Pat. No. 5,874,025 requires the addition ofpolyaspartic acid, its salts, or its derivatives in the preparation of awood preservative which exhibits reduced leaching of alkanolamine.However, the polyaspartic acid is used at least partially instead of thealkanolamine, with the formation of the biocidal copper alkanolaminecomplex partially or completely eliminated.

U.S. Pat. No. 5,186,947 also discloses a method of preparing watersoluble copper complexes using polyamines as the solubilizing agents forcopper. In this invention, aliphatic acids are used in the formulationsto improve the fixation and reduce the leaching of copper from wood.This patent also teaches that polyacrylic acids may be added tocopper-polyethylenimine (Cu-PEI) formulations. We have discovered thatthe addition of polyacrylic acid to Cu-PEI results in the formation of acopper precipitate. The precipitation of copper from a wood preservativeformulation is undesirable because it reduces the amount of copperpresent in solution which is able to penetrate into the wood.Additionally, precipitated copper will remain on the surface of thewood, potentially contributing to an uneven surface appearance of thetreated wood. This is undesirable in providing an aqueous woodpreservative formulation useful in providing wood products that areaesthetically acceptable to the public, yet preserved from thedestructive agencies of wood.

Accordingly, the discovery that certain vinyl based polymers aid indecreasing the leaching of metal from treated wood while still providingclear aqueous formulations was entirely unexpected. Thus, the need toprovide aqueous copper amine complexes that are suitable for use totreat wood, yet minimize the copper leaching from treated wood whenexposed to water and do not result in precipitation is addressed by theincorporation of polyethylenimine and the vinyl based polymerspoly(vinyl alcohol), polyacrylamide, poly(N-vinyl pyrrolidone), andpoly(N-isopropyl acrylamide) into copper amine formulations.

SUMMARY

The present invention relates to a method and a wood preservingcomposition which comprises mixtures of a preservative metal compound ina preservative amount, complexing agents selected from ethanolamines,polyethylenimine, ammonia or a mixture of these compounds, and a vinylbased polymer selected from poly(vinyl alcohol) (PVA), poly(acrylamide)(PA), poly(N-vinyl pyrrolidone) (PVP) and poly(N-isopropyl acrylamide)(PNIPAM). The resulting metal amine solution can then be used toformulate a variety of metal-based cellulosic preserving products whichdo not form precipitates.

Therefore, in one embodiment, provided herein is an aqueous preservativecomposition for treating cellulose based products including woodcomprising a preservative metal selected from the group consisting ofcopper, cobalt, aluminum, iron, lead, tin, cadmium, nickel, chromium,zinc, silver and mixtures thereof in a preservative amount; anon-polymeric amine compound in an amount sufficient to solubilize thepreservative metal; a polymeric amine compound such as apolyethylenimine compound in an amount sufficient to form a chelationcomplex with the metal; and a vinyl based polymer selected from thegroup consisting of poly(vinyl alcohol), polyacrylamide, poly(N-vinylpyrrolidone), poly(N-isopropyl acrylamide) and mixtures thereof. Thiscomposition is free of poly-aspartic acid or its derivatives andprovides an aqueous preservative composition wherein no precipitate ispresent. In one embodiment, the aqueous preservative compositioncomprises between about 0.01% and about 15% by weight solubilizedcopper; between about 0.15% and about 10% by weight non-polymeric amine;between about 0.01% and about 40% by weight polyethylenimine having anumber average molecular weight between about 100 and about 70,000; andbetween about 0.01% and about 8% poly(vinyl alcohol).

In another embodiment, provided is an aqueous preservative compositioncomprising a preservative metal, a polymeric amine or a non-polymericamine; and a vinyl based polymer. In one embodiment, the preservativecomposition comprises between about 0.01% and about 15% by weightsolubilized copper; between about 0.15% and about 50% by weightnon-polymeric amine; and between about 0.01% and about 30% poly(vinylalcohol). In another embodiment, the preservative composition comprisesbetween about 0.01% and about 15% by weight solubilized copper; betweenabout 0.01% and about 40% by weight polymeric amine; and between about0.01% and about 30% poly(vinyl alcohol).

Also provided herein is a method for treating a cellulose based productincluding wood by applying to the cellulose based product an aqueouspreservative composition for treating cellulose based products includingwood prepared according to the invention herein.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a chart showing the effect of the addition of PEI on theleaching of copper from wood.

FIG. 2 is a chart showing the effect of poly vinyl alcohol on theleaching of copper.

FIG. 3 is a chart showing the effect of combining polyethylenimine andpoly (vinyl alcohol) in a wood preservative on the leaching of copper.

FIG. 4 is a chart showing the effect of combining polyethylenimine andammonia in a wood preservative on the leaching of copper.

DETAILED DESCRIPTION

Unless specifically stated otherwise, for example, as in the examples,all numerical values contained herein are intended to be modified by theterm “about.” Also, unless specifically stated otherwise, all percentvalues contained within are weight percent.

American Wood-Preservers' Association (AWPA) Standard E11-97 “StandardMethod of Determining the Leachability of Wood Preservatives” was usedto evaluate the leaching of copper from the treated wood. The results ofthe leaching evaluations are contained in FIGS. 1-4.

All materials used in the preparation of the wood preservativecompositions according to the invention herein are readily availablefrom commercial suppliers.

A method for the preparation of a preservative metal amine complexsolution is provided that, in a preferred embodiment, efficientlyreduces the leaching of metal from treated wood and does not result inthe formation of precipitates. For purposes of this application, themetal amine solution is obtained from a metal bearing material that isnormally soluble or insoluble in water, for example, copper, cobalt,aluminum, iron, lead, tin, cadmium, nickel, chromium, silver and zinc.The preferred metal bearing material is copper. The preservativecompositions of the present invention do not contain poly-aspartic acidor its derivatives.

The amount and concentration of workable treating solution applied to aparticular substrate will depend upon many factors such as the nature ofthe substrate (e.g., species of wood), its end use, its geographiclocation, the method of application and the nature of the attack to beprevented. A preservative is usually applied to a substrate in aquantity sufficient to produce a desired preservative end point andthus, actual quantities may vary broadly. In general, an effectivepreservative treating solution will contain from 0.01% to 15% ofpreservative metal salt, depending upon the salt selected. More commonlythis range will vary from between 0.5% to 10% based on the preservativemetal salt content.

In preparing these solutions for application to a substrate, aconcentrated stock solution of preservative metal salt is first made oris obtained as a commercial preparation and is thereafter combined witha solution of vinyl based polymer and optionally diluted to a finalworking solution having the desired concentration. Of course, becausethe molecular weights of the various metals and metal compounds will bedifferent, the weight percent of metal compound present in the metalcomplex solutions of the invention herein will depend upon which metalor metal compound is selected. The selection of a particular metal ormetal compound is within the purview of one of ordinary skill in theart. For example, when the metal compound is copper carbonate, between0.09% to 25.0% may be used.

Methods for solubilizing metals are well known to those of ordinaryskill in the art. For example, a copper concentrate solution is preparedby mixing water with all the amine ligands or chelating agents firstfollowed by adding copper compounds and stirring the mixture for about0.5 hours to 6 hours depending upon the copper source. The final productmay be pH adjusted by using carbon dioxide.

A workable solution is prepared by diluting the solubilized metalconcentrate. The vinyl based polymer is added to the solubilized metalconcentrate solution as a liquid solution along with water as needed fordilution. The vinyl based polymer is either obtained commercially as asolution or, more preferably, is obtained from a commercial supplier indry form and formed into a solution according to the manufacturer'sguidelines. The solubilized metal concentrate solution and vinyl basedpolymer solution may be combined with water as needed immediately priorto application to the substrate being treated.

An exemplary method to prepare the solubilized metal concentratesolution uses water soluble or water insoluble copper metal and coppercompounds, such as copper sulfate, copper acetate, copper formate,copper chloride, copper nitrate, basic copper carbonate, copperhydroxide, copper oxide, cupric oxide, cuprous oxide, copper borates,etc. These copper compounds are normally prone to form water solublecopper complexes with non-polymeric amine containing organic compounds.Although the preferred non-polymeric amine containing compounds areethanolamines which possess the structure as shown below, other aminesthat can also be used are diethanolamine, triethanolamine, ethylamine,diethylamine, ethylenediamine, etc.

Copper or copper compounds generally also have significant solubilitiesin polymeric amines, such as polethylenimine. Thus, the copper or coppercompounds can be solubilized in the polymeric amine component which isparticularly convenient if the non-polymeric amine component is omitted.

The structure of preferred ethanolamines is provided below:

wherein R₁, R₂, R₃, R₄, R₅, R₆ independently=H, —CH₃, or —C₂H₅.

The weight percent of the non-polymeric amine containing compound willvary depending upon which non-polymeric amine containing compound isused. For example, when the non-polymeric amine containing compound ismonoethanolamine, between 0.15% and 7.20% can be used. When more thanone non-polymeric amine containing compound is used in the metal complexsolutions of the invention herein, the total non-polymeric aminecontaining compound may be as much as 10.0%.

However, if the polymeric amine compound is omitted, the aqueouspreservative composition preferably comprises between about 0.15% andabout 50% by weight non-polymeric amine.

For economic reasons, small amounts of ammonium hydroxide or otherammonia salts such as ammonium bicarbonate, ammonium carbonate, ammoniumsulfate, ammonium phosphate, etc. may be used to replace part of theethanolamine. When used, between 0.02% and 0.6% of ammonium compound canbe used to replace part of the ethanolamine.

Polyethylenimine (PEI) is a polymeric amine complexing agent. PEI can becharacterized by the repeating chemical unit denoted as —[CH₂—CH₂—NH]—.The amine groups in PEI are either primary, secondary or tertiary aminegroups in the approximate ratio 1:2:1 with a branching site every 3-3.5nitrogen atoms along any given chain segment. PEI is prepared forexample by the ring opening polymerization of ethylenimine (oraziridine) catalyzed by an acid. The high degree of branching is thoughtto be due to the chain transfer reaction of amine groups with thequaternary aziridinium ion. The number-average molecular weight(determined by Gel permeation Chromatography (GPC)) of PEI suitable forcomplexing copper ranges from 100 to 70,000.

A variety of polymeric amine compounds can be used in the woodpreservative formulation of the present invention. However,polyethylenimine (PEI) is preferred. PEI can form chelating complexeswith copper in cupric form. In most research on the subject, a 3:1complexation ratio of PEI to copper has been proposed. A very importantaspect of PEI is that this polymeric material has many cationic aminegroups that are available for reaction with anionic substrates, such ascellulose or lignin in wood. Therefore, PEI can not only complex withcopper to form water soluble complexes, it can also fix these complexesto the wood matrix. To reduce the viscosity of formulations and foreconomic purpose, PEI is often used as a ligand to replace part of theethanolamines, with or without ammonia, to form copper complexes. PEIcan also be used as an additive to the already formed copper aminecomplexes. Addition of PEI to the copper formulations reduces the copperleaching from treated wood by 50% as illustrated in FIG. 1.

The concentration of PEI can vary with the applications. For example,when PEI is used as a complexing agent to form copper complexes, with orwithout the use of other amine ligands, concentrations of PEI vary from1.0% to 40.0%. When PEI is used as an additive to the formed copperamine solutions, the concentration of PEI can vary from 0.01% to 2.0%.

Copper leaching from treated wood is greatly reduced when certain vinylbased polymers are added to the copper amine formulations. Vinyl basedpolymers which do not result in the formation of copper precipitateswhen used at workable concentrations are poly(vinyl alcohol),polyacrylamide, poly(N-vinyl pyrrolidone), and poly(N-isopropylacrylamide). The general structure of these polymers is given below:

wherein R=—CONH₂, —CONHCH(CH₃)₂,

—OH, and —CONH₂. The preferred vinyl based polymer is poly(vinylalcohol) (PVA).

PVA is formed, for example, from the polymerization of vinyl acetatemonomer followed by hydrolysis using sodium hydroxide. The degree ofpolymerization suitable for this application is between 2 and 5000. Thedegree of hydrolysis varies from 10% to 100%. Concentrations ofcopper-fixing vinyl based polymer vary from 0.01% to 8.0% with 0.1%-1.0%being the preferred range. FIG. 2 demonstrates that the copper leachingfrom wood is reduced by about 40% when PVA is added to the coppersolutions. Concentrations of vinyl based polymer greater than 8% willtend to result in the formation of copper precipitates in the finaltreating solution.

The leaching of copper from the treated wood can be further reduced bycombining the polymeric amine compound and the vinyl-based polymercompound, as shown in FIG. 3 for PEI and PVA.

It has also been discovered that the addition of a small amount ofammonia to in FIG. 4 for PVA and PEI, further reduces the leaching ofcopper leaching from wood. The amount of ammonia added to the metalcomplex solution will be between 0.02% and 3.0%.

The resulting copper amine solution can be mixed with a variety ofbiocides such as fungicides and insecticides to produce a formulationsuitable for the preservation of wood and other cellulose-basedmaterials. Typical biocides that can be used for this formulation arefungicides such as azoles, quaternary ammonium compounds, etc. as wellas various insecticides.

The treating solution may be applied, for example, to wood by dipping,soaking, spraying, brushing, or any other well known means. Vacuumand/or pressure techniques may also be used to impregnate the wood inaccord with this invention including both the “Empty Cell” process andthe “Full Cell” process which are well known to those of ordinary skillin the art.

The invention will be better understood by way of the following examplesand comparative examples which are intended to illustrate but not limitthe scope of the claims. Examples 1-4 are workable solutions containingpolyacrylamide. Examples 5-8 are workable solutions containingpoly(vinyl pyrrolidone). Examples 9-16 are workable solutions containingpoly(vinyl alcohol). Examples 17-29 are metal concentrate formulationswhich can be mixed with solutions of vinyl based polymers to formworkable solutions. The metal concentrate formulations can be optionallydiluted with water prior to making workable solutions. The workablesolutions can be further combined with co-biocides to prepare woodpreserving treating solutions.

Examples of Polyacrylamide Workable Solutions:

EXAMPLES 1-4 EXAMPLE 1

Ingredient Percent PEI Mw. = 10,000 0.08 Monoethanolamine 0.49 Ammonia0.07 Basic copper carbonate 0.45 Polyacrylamide Mw. = 1,500 0.25 Water98.66Appearance - Clear

EXAMPLE 2

Ingredient Percent PEI Mw. = 10,000 0.08 Monoethanolamine 0.49 Ammonia0.07 Basic copper carbonate 0.45 Polyacrylamide Mw. = 1,500 0.50 Water98.41Appearance - Clear

EXAMPLE 3

Ingredient Percent PEI Mw. = 10,000 0.16 Monoethanolamine 0.98 Ammonia0.14 Basic copper carbonate 0.91 Polyacrylamide Mw. = 1,500 0.25 Water97.56Appearance - Clear

EXAMPLE 4

Ingredient Percent PEI Mw. = 10,000 0.16 Monoethanolamine 0.98 Ammonia0.14 Basic copper carbonate 0.91 Polyacrylamide Mw. = 1,500 0.50 Water97.31Appearance - Clear

EXAMPLE 5

Ingredient Percent PEI Mw. = 10,000 0.08 Monoethanolamine 0.49 Ammonia0.07 Basic copper carbonate 0.45 Poly(vinyl pyrrolidone) Mw. = 55,0000.25 Water 98.66Appearance - Clear

EXAMPLE 6

Ingredient Percent PEI Mw. = 10,000 0.08 Monoethanolamine 0.49 Ammonia0.07 Basic copper carbonate 0.45 Poly(vinyl pyrrolidone) Mw. = 55,0000.50 Water 98.41Appearance - Clear

EXAMPLE 7

Ingredient Percent PEI Mw. = 10,000 0.16 Monoethanolamine 0.98 Ammonia0.14 Basic copper carbonate 0.91 Poly(vinyl pyrrolidone) Mw. = 55,0000.25 Water 97.56Appearance - Clear

EXAMPLE 8

Ingredient Percent PEI Mw. = 10,000 0.16 Monoethanolamine 0.98 Ammonia0.14 Basic copper carbonate 0.91 Poly(vinyl pyrrolidone) Mw. = 55,0000.50 Water 97.31Appearance - ClearExamples of Poly(Vinyl Alcohol) Workable Solutions:

EXAMPLES 9-16 EXAMPLE 9

Ingredient Percent Monoethanolamine 1.71 Basic copper carbonate 1.01PVA, Mw. = 15,000 0.20 Water 97.08Appearance - Clear

EXAMPLE 10

Ingredient Percent Monoethanolamine 1.40 N-methylethanolamine 0.51 Basiccopper carbonate 0.09 PVA, Mw. = 15,000 0.40 Water 97.60Appearance - Clear

EXAMPLE 11

Ingredient Percent PEI, Mw. = 5000 0.69 Monoethanolamine 1.32 Basiccopper carbonate 1.01 PVA, Mw. = 20,000 0.40 Water 96.58Appearance - Clear

EXAMPLE 12

Ingredient Percent PEI Mw. = 10,000 0.69 Monoethanolamine 1.32 Basiccopper carbonate 1.01 PVA, Mw. = 15,000 0.40 Water 96.58Appearance - Clear

EXAMPLE 13

Ingredient Percent PEI Mw. = 70,000 0.40 Monoethanolamine 1.21 Ammonia0.03 Basic copper carbonate 0.09 PVA, Mw. = 15,000 0.40 Water 97.87Appearance - Clear

EXAMPLE 14

Ingredient Percent PEI Mw. = 5,000 0.17 Monoethanolamine 0.47 Ammonia0.03 Basic copper carbonate 0.45 PVA, Mw. = 15,000 0.40 Water 98.48Appearance - Clear

EXAMPLE 15

Ingredient Percent PEI Mw. = 10,000 0.38 Monoethanolamine 1.05 Ammonia0.07 Basic copper carbonate 1.01 PVA, Mw. = 15,000 0.40 Water 97.09Appearance - Clear

EXAMPLE 16

Ingredient Percent PEI Mw. = 70,000 0.19 Monoethanolamine 0.53 Ammonia0.04 Basic copper carbonate 0.50 PVA, Mw. = 15,000 0.40 Water 98.34Appearance - ClearExamples of PEI Metal Concentrate Formulations:

EXAMPLES 17-29 EXAMPLE 17

Ingredient Percent PEI Mw. = 5000 12.5 Monoethanolamine 24.0 Basiccopper carbonate 18.2 Water 45.3Appearance - Clear

EXAMPLE 18

Ingredient Percent PEI Mw. = 10,000 12.5 Monoethanolamine 24.0 Basiccopper carbonate 18.2 Water 45.3Appearance - Clear

EXAMPLE 19

Ingredient Percent PEI Mw. = 10,000 6.6 Monoethanolamine 24.0 Basiccopper carbonate 18.2 Water 51.2Appearance - Clear

EXAMPLE 20

Ingredient Percent PEI Mw. = 10,000 6.6 Monoethanolamine 14.4N-Methylethanolamine 11.8 Basic copper carbonate 18.2 Water 49.0Appearance - Clear

EXAMPLE 21

Ingredient Percent PEI Mw. = 10,000 6.6 Monoethanolamine 14.4N,N-Dimethylethanolamine 14.0 Basic copper carbonate 18.2 Water 46.8Appearance - Clear

EXAMPLE 22

Ingredient Percent PEI Mw. = 6,000 6.6 Monoethanolamine 14.4N-Ethylethanolamine 14.0 Basic copper carbonate 18.2 Water 46.8Appearance - Clear

EXAMPLE 23

Ingredient Percent PEI Mw. = 8,000 6.6 Monoethanolamine 14.4Monoisopropanolamine 11.8 Basic copper carbonate 18.2 Water 49.0Appearance - Clear

EXAMPLE 24

Ingredient Percent PEI Mw. = 5,000 6.6 Monoethanolamine 22.0 Ammonia 0.6Basic copper carbonate 18.2 Water 52.6Appearance - Clear

EXAMPLE 25

Ingredient Percent PEI Mw. = 10,000 6.6 Monoethanolamine 22.0 Ammonia0.6 Basic copper carbonate 18.2 Water 52.6Appearance - Clear

EXAMPLE 26

Ingredient Percent PEI Mw. = 70,000 6.6 Monoethanolamine 22.0 Ammonia0.6 Basic copper carbonate 18.2 Water 52.6Appearance - Clear

EXAMPLE 27

Ingredient Percent PEI Mw. = 5,000 7.0 Monoethanolamine 19.2 Ammonia 1.3Basic copper carbonate 18.2 Water 54.3Appearance - Clear

EXAMPLE 28

Ingredient Percent PEI Mw. = 10,000 7.0 Monoethanolamine 19.2 Ammonia1.3 Basic copper carbonate 18.2 Water 54.3Appearance - Clear

EXAMPLE 29

Ingredient Percent PEI Mw. = 70,000 7.0 Manoethanalamine 19.2 Ammonia1.3 Basic copper carbonate 18.2 Water 54.3Appearance - Clear

COMPARATIVE EXAMPLES

The compositions shown in the following comparative examples result in acloudy solution and the presence of white precipitate.

Comparative Example 1

Ingredient Percent PEI Mw. = 10,000 0.08 Monoethanolamine 0.49 Ammonia0.07 Basic copper carbonate 0.45 Poly(acrylic acid)Mw. = 2,000 0.18Water 98.73Appearance - Cloudy

Comparative Example 2

Ingredient Percent PEI Mw. = 10,000 0.08 Monoethanolamine 0.49 Ammonia0.07 Basic copper carbonate 0.45 Poly(acrylic acid)Mw. = 2,000 0.36Water 98.55Appearance - Cloudy

Comparative Example 3

Ingredient Percent PEI Mw. = 10,000 0.16 Monoethanolamine 0.98 Ammonia0.14 Basic copper carbonate 0.91 Poly(acrylic acid)Mw. = 2,000 0.18Water 97.63Appearance - Cloudy

Comparative Example 4

Ingredient Percent PEI Mw. = 10,000 0.16 Monoethanolamine 0.98 Ammonia0.14 Basic copper carbonate 0.91 Poly(acrylic acid)Mw. = 2,000 0.36Water 97.45Appearance - Cloudy

In addition, various known additives may be combined with thepreservative compositions formulated according to the present inventionwithout substantially affecting the preservative capacity of the presentcomposition. For instance, coloring agents, waxes, resins, aqueoussolutions, various emulsions and other ingredients may be added to thepresent composition where such additional properties are desirable.

A wide variety of woods can be preserved in accordance with thisinvention, including hard and/or softwoods. Many other types ofcellulose based materials including paper, particle board, textiles,rope and other such well known cellulose by-products may also be treatedwith this preservative composition, provided the material is capable ofwithstanding the treatment process.

It is to be fully understood that all of the foregoing examples areintended to be merely illustrative and not to be construed orinterpreted as being restrictive or otherwise limiting of the presentinvention, excepting as set forth and defined in the hereto appendedclaims.

1. An aqueous preservative composition for treating a cellulose-basedproduct, said composition comprising: a preservative metal selected fromthe group consisting of copper, cobalt, aluminum, iron, lead, tin,cadmium, nickel, chromium, silver, zinc and mixtures thereof in apreservative amount; a non-polymeric amine compound in an amountsufficient to solubilize the preservative metal; a polyethyleniminecompound in an amount sufficient to form a chelation complex with themetal; and a vinyl based polymer selected from the group consisting ofpoly(vinyl alcohol), polyacrylamide, poly(N-vinyl pyrrolidone),poly(N-isopropyl acrylamide) and mixtures thereof; wherein noprecipitate is present in the aqueous wood preservative composition andwherein said wood preservative composition is free of polyaspartic acid.2. The composition of claim 1 further comprising an ammonia salt.
 3. Thecomposition of claim 1 further comprising ammonia.
 4. The composition ofclaim 1 wherein the preservative metal is copper bearing material. 5.The composition of claim 4 wherein the copper bearing material isselected from the group consisting of copper metal, copper sulfate,copper acetate, copper formate, copper chloride, copper nitrate, basiccopper carbonate, copper hydroxide, cupric oxide, cuprous oxide, copperborates and mixtures thereof.
 6. The composition of claim 1 wherein thenon-polymeric amine is selected from the group consisting oftriethanolamine, ethylamine, diethylamine, ethylenediamine,ethanolamines having the following structural formula I:

wherein R₁, R₂, R₃, R₄, R₅, R₆ independently=H, —CH₃, or —C₂H₅; andmixtures thereof.
 7. The composition of claim 1 wherein thenon-polymeric amine is present at a concentration between about 0.15%and about 10% by weight.
 8. The composition of claim 1 wherein thenon-polymeric amine is present at a concentration between about 0.15%and about 7.20% by weight.
 9. The composition of claim 1 wherein thepolyethylenimine compound has a molecular weight between about 100 andabout 70,000.
 10. The composition of claim 1 wherein thepolyethylenimine compound is present at a concentration between about0.01% and about 40.0% by weight.
 11. The composition of claim 1 whereinthe polyethylenimine compound is present at a concentration betweenabout 0.1% and about 2.0% by weight.
 12. The composition of claim 1wherein the polyethylenimine compound is present at a concentrationbetween about 0.01% and about 2% by weight.
 13. The composition of claim1 wherein the vinyl based polymer is present at a concentration betweenabout 0.01% and about 8% by weight.
 14. The composition of claim 1wherein the vinyl based polymer is present at a concentration of fromabout 0.1% to about 1% by weight.
 15. The composition of claim 1 furthercomprising a biocide.
 16. The composition of claim 15 wherein thebiocide is selected from the group consisting of fungicides,insecticides and mixtures thereof.
 17. The composition of claim 16wherein the fungicide is selected from the group consisting of azoles,quaternary ammonium compounds and mixtures thereof.
 18. The compositionof claim 1 wherein the cellulose based product is wood.
 19. An aqueouspreservative composition for treating a cellulose-based product, saidcomposition comprising: between about 0.01% and about 15% by weightsolubilized copper; between about 0.15% and about 10% by weightnon-polymeric amine; between about 0.01% and about 40% by weightpolyethylenimine having a number average molecular weight between about100 and about 70,000; and between about 0.01% and about 8% poly(vinylalcohol); wherein said wood preservative composition is free ofpolyaspartic acid.
 20. The composition of claim 18 wherein the cellulosebased product is wood.
 21. A method for treating a cellulose basedproduct said method comprising: applying to the cellulose based productan aqueous preservative composition for treating cellulose basedproducts including wood comprising: a preservative metal selected fromthe group consisting of copper, cobalt, aluminum, iron, lead, tin,cadmium, nickel, chromium, silver, zinc and mixtures thereof in apreservative amount; a non-polymeric amine compound in a solubilizingamount; a polyethylenimine compound in a chelation complex formingamount; and a vinyl based polymer selected from the group consisting ofpoly(vinyl alcohol), polyacrylamide, poly(N-vinyl pyrrolidone),poly(N-isopropyl acrylamide) and mixtures thereof; wherein noprecipitate is present in the aqueous wood preservative composition, andwherein said wood preservative composition is free of polyaspartic acid.22. The method of claim 21 wherein the aqueous preservative compositionfurther comprises an ammonia salt.
 23. The method of claim 21 whereinthe aqueous preservative composition further comprises ammonia.
 24. Themethod of claim 21 wherein the preservative metal is a copper bearingmaterial.
 25. The method of claim 24 wherein the copper bearing materialis selected from the group consisting of copper metal, copper sulfate,copper acetate, copper formate, copper chloride, copper nitrate, basiccopper carbonate, copper hydroxide, cupric oxide, cuprous oxide, copperborates and mixtures thereof.
 26. The method of claim 21 wherein thenon-polymeric amine is selected from the group consisting oftriethanolamine, ethylamine, diethylamine, ethylenediamine,ethanolamines having the following structural formula I:

wherein R₁, R₂, R₃, R₄, R₅, R₆ independently=H, —CH₃, or —C₂H₅; andmixtures thereof.
 27. The method of claim 21 wherein thepolyethylenimine compound has a molecular weight between about 100 andabout 70,000.
 28. The method of claim 21 wherein the polyethyleniminecompound is present at a concentration between about 0.01% and about40.0% by weight.
 29. The method of claim 21 wherein the polyethyleniminecompound is present at a concentration between about 1.0% and about40.0% by weight.
 30. The method of claim 21 wherein the vinyl basedpolymer is present at a concentration between about 0.01% and about 8%by weight.
 31. The method of claim 21 wherein the aqueous preservativecomposition further comprises a biocide.
 32. The method of claim 31wherein the biocide is selected from the group consisting of fungicides,insecticides and mixtures thereof.
 33. The method of claim 32 whereinthe fungicide is selected from the group consisting of azoles,quaternary ammonium compounds and mixtures thereof.
 34. The method ofclaim 21 wherein the cellulose based product is flooded with thepreservative composition under vacuum.
 35. The composition of claim 21wherein the cellulose based product is wood.
 36. An aqueous preservativecomposition for treating a cellulose-based product, said compositioncomprising: a preservative metal selected from the group consisting ofcopper, cobalt, aluminum, iron, lead, tin, cadmium, nickel, chromium,silver, zinc and mixtures thereof in a preservative amount; one memberof the group consisting of: a non-polymeric amine compound in an amountsufficient to solubilize the preservative metal and a polyethyleniminecompound in an amount sufficient to form a chelation complex with themetal; and a vinyl based polymer selected from the group consisting ofpoly(vinyl alcohol), polyacrylamide, poly(N-vinyl pyrrolidone),poly(N-isopropyl acrylamide) and mixtures thereof; wherein noprecipitate is present in the aqueous wood preservative composition andwherein said wood preservative composition is free of polyaspartic acid.37. The composition of claim 36 further comprising an ammonia salt. 38.The composition of claim 36 further comprising ammonia.
 39. Thecomposition of claim 36 wherein the preservative metal is copper bearingmaterial.
 40. The composition of claim 39 wherein the copper bearingmaterial is selected from the group consisting of copper metal, coppersulfate, copper acetate, copper formate, copper chloride, coppernitrate, basic copper carbonate, copper hydroxide, cupric oxide, cuprousoxide, copper borates and mixtures thereof.
 41. The composition of claim36 wherein the non-polymeric amine is selected from the group consistingof triethanolamine, ethylamine, diethylamine, ethylenediamine,ethanolamines having the following structural formula I:

wherein R₁, R₂, R₃, R₄, R₅, R₆ independently=H, —CH₃, or —C₂H₅; andmixtures thereof.
 42. The composition of claim 36 wherein thenon-polymeric amine is present at a concentration between about 0.15%and about 50% by weight.
 43. The composition of claim 36 wherein thenon-polymeric amine is present at a concentration between about 0.15%and about 7.20% by weight.
 44. The composition of claim 36 wherein thepolyethylenimine compound has a molecular weight between about 100 andabout 70,000.
 45. The composition of claim 36 wherein thepolyethylenimine compound is present at a concentration between about0.01% and about 40.0% by weight.
 46. The composition of claim 36 whereinthe polyethylenimine compound is present at a concentration betweenabout 0.1% and about 2.0% by weight.
 47. The composition of claim 36wherein the polyethylenimine compound is present at a concentrationbetween about 0.01% and about 2% by weight.
 48. The composition of claim36 wherein the vinyl based polymer is present at a concentration betweenabout 0.01% and about 30% by weight.
 49. The composition of claim 36wherein the vinyl based polymer is present at a concentration of fromabout 0.1% to about 1% by weight.
 50. The composition of claim 36further comprising a biocide.
 51. The composition of claim 36 whereinthe biocide is selected from the group consisting of fungicides,insecticides and mixtures thereof.
 52. The composition of claim 36wherein the fungicide is selected from the group consisting of azoles,quaternary ammonium compounds and mixtures thereof.
 53. The compositionof claim 36 wherein the cellulose based product is wood.
 54. A methodfor treating a cellulose based product, said method comprising: applyingto the cellulose based product an aqueous preservative composition fortreating cellulose based products including wood comprising: apreservative metal selected from the group consisting of copper, cobalt,aluminum, iron, lead, tin, cadmium, nickel, chromium, silver, zinc andmixtures thereof in a preservative amount; one member of the groupconsisting of: a non-polymeric amine compound in an amount sufficient tosolubilize the preservative metal and a polyethylenimine compound in anamount sufficient to form a chelation complex with the metal; and avinyl based polymer selected from the group consisting of poly(vinylalcohol), polyacrylamide, poly(N-vinyl pyrrolidone), poly(N-isopropylacrylamide) and mixtures thereof; wherein no precipitate is present inthe aqueous wood preservative composition, and wherein said woodpreservative composition is free of polyaspartic acid.
 55. The method ofclaim 54 wherein the aqueous preservative composition further comprisesan ammonia salt.
 56. The method of claim 54 wherein the aqueouspreservative composition further comprises ammonia.
 57. The method ofclaim 54 wherein the preservative metal is a copper bearing material.58. The method of claim 57 wherein the copper bearing material isselected from the group consisting of copper metal, copper sulfate,copper acetate, copper formate, copper chloride, copper nitrate, basiccopper carbonate, copper hydroxide, cupric oxide, cuprous oxide, copperborates and mixtures thereof.
 59. The method of claim 54 wherein thenon-polymeric amine is selected from the group consisting oftriethanolamine, ethylamine, diethylamine, ethylenediamine,ethanolamines having the following structural formula I:

wherein R₁, R₂, R₃, R₄, R₅, R₆ independently=H, —CH₃, or —C₂H₅; andmixtures thereof.
 60. The method of claim 54 wherein thepolyethylenimine compound has a molecular weight between about 100 andabout 70,000.
 61. The method of claim 54 wherein the polyethyleniminecompound is present at a concentration between about 0.01% and about40.0% by weight.
 62. The method of claim 54 wherein the polyethyleniminecompound is present at a concentration between about 0.1% and about 2.0%by weight.
 63. The composition of claim 54 wherein the non-polymericamine is present at a concentration between about 0.15% and about 50% byweight.
 64. The composition of claim 54 wherein the non-polymeric amineis present at a concentration between about 0.15% and about 7.20% byweight.
 65. The method of claim 54 wherein the vinyl based polymer ispresent at a concentration between about 0.01% and about 30% by weight.66. The method of claim 54 wherein the aqueous preservative compositionfurther comprises a biocide.
 67. The method of claim 54 wherein thebiocide is selected from the group consisting of fungicides,insecticides and mixtures thereof.
 68. The method of claim 67 whereinthe fungicide is selected from the group consisting of azoles,quaternary ammonium compounds and mixtures thereof.
 69. The method ofclaim 54 wherein the cellulose based product is flooded with thepreservative composition under vacuum.
 70. The composition of claim 54wherein the cellulose based product is wood.